Tetrahydrofuran polymers



United States Patent ABSTRACT OF THE DISCLOSURE Tetrahydrofuran is polymerized with a monomer system made up of either cyclopentadiene or cyclopentadiene and an oxirane or oxetane compound with either a mono or bis triarylmethyl carbonium ion salt catalyst.

The present invention relates to new tetrahydrofurancyclopentadiene polymers and a method for their preparation. More particularly, the invention is directed to copolymers of tetrahydrofuran and cyclopentadiene and also terpolymers of tetrahydrofuran, cyclopentadiene and a third oxirane or oxetane comonomer and to a method for their preparation.

Various copolymers of tetrahydrofuran (tetramethylene-oxide) with other materials have been reported as being prepared with various types of polymerization initiators. Meerwein, in German Patent No. 914,438, found that copolymers of tetrahydrofuran with ethylene oxide could be prepared utilizing borontrifluoride or antimony trichloride but not aluminum chloride or zinc chloride polymerization initiators. Most of the polymers described as being formed with the catalyst systems of the prior art .are characterized as being mobile or viscous liquids.

Now in accordance with this invention, polymer products capable of a wide variation in form and utility are prepared by polymerizing tetrahydrofuran with a monomer system made up of either cyclopentadiene alone or cyclopentadiene and an oxirane or oxetane compound. The polymerization is conveniently conducted at relatively low temperatures and at mild pressures in the presence of aromatic diluents or in bulk with a mono or bis dior tri-aryl methyl carbonium ion salt catalyst. Depending upon the proportions of monomers in the final polymer composition, the products of this invention may be elastomers which can be vulcanized with sulfur and accelera tors, surface coatings which may be applied from a solvent vehicle to form crosslinked films on air drying or thermoplastic compositions.

As stated above, the polymers encompassed by the present invention include copolymers of tetrahydrofuran with cyclopentadiene as well as terpolymers of tetrahydrofuran, cyclopentadiene, and an oxirane (1,2-epoxide) or oxetane (1,3-epoxide) compound. The generic formula for these epoxide compounds may be represented as:

wherein any of R through R is a hydrogen, a C to C alkyl group, a C to C haloalkyl, a C to C aryl or a C to C ether. Preferably, the value of the Rs are C -C alkyls or haloalkyls. The value of n in the above formula is equal to 0 or 1 and when n is equal to 0 it is necessary that at least either R or R be a hydrogen radical. The R groupings may be the same or a different moiety within the limits of the above formula.

Representative non-limiting examples of useful oxirane and oxetane compounds include ethylene oxide, propylene oxide, epichlorohydrin, trimethylene oxide, styrene oxide, allyl glycidyl ether, 2-phenyl oxetane, 3,3-bis (chloromethyl) oxetane, 1,2-dodecane oxide, 1,4-cyclohexane oxide, and l,2-epoxy-5,6 trans-9,l0cis-cyclododecadiene. The preferred epoxide compounds are: propylene oxide, 3,3-bis (chloromethyl) oxetane and ally] glycidyl ether.

The present polymerization process may be carried out in bulk such as in an excess of tetrahydrofuran. Additionally, solvent polymerization techniques may also be used. Aromatic hydrocarbons that are liquid at the conditions of temperature and pressure used in the polymerization reaction are preferred for use in the process of this invention. Representative examples of suitable solvents include benzene, toluene, ethylbenzene, xylene, nitrobenzene, and the like. Mixtures of aromatic solvents with alicyclic solvents, for example, toluene and cyclohexane, may be used. Halogenated materials such as methyl chloride or methylene chloride should be avoided.

The catalyst system employed in preparing the copolymers and terpolymers of this invention comprises at least one dior tri-arylmethyl carbonium ion salt. Mono or bis carbonium ion salts are effective catalysts. The general structure of the desired carbonium ion salt may be represented by the following formula:

wherein Ar is a phenyl or naphthyl group or an alkylsubstituted phenyl or naphthyl group. Each of the Ar groups may be the same or a different aromatic moiety. The value of M in the above formula is a cation which may be selected from the group consisting of antimony, tin, aluminum, boron, zinc, iron, titanium, zirconium, vanadium, and galenium. The value of x represents a common halide having an atomic number of less than 53, i.e. chlorine, bromine, fluorine, or a mixture of the same. The value of x is an integer of from 2 to 3; the sum of x and y must be equal to 3; z is equal to the highest valence of the cation M+1; a is an integer of from 0 to 1 and when a equals 0, R is hydrogen and when a is equal to l, R is an ethylene group (-C H Representative examples of useful arylmethyl carbonium ion salt catalysts include triphenylmethyl antimony hexachloride (triphenylmethyl hexachloroantimonate),

triphenylmethyl aluminum tetrachloride, triphenylmethyl tin pentachloride, triphenylmethyl boron tetrachloride, triphenylmethyl boron tetrafluoride, triphenylmethyl diethyl aluminum dichloride, triphenylmethyl-chloro-boron trifiuoride, triphenylmethyl-bromo-antimony pentachloride, diphenylmethyl antimony hexachloride, bis[4,4'-di phenylmethyl1bibenzyl bis(hexachloroantimonate), etc.

The preferred aryl group in the carbonium ion catalyst is a phenyl radical and the preferred cation is antimony. The most preferred salt is triphenylmethyl antimony hexachloride. The total amount of catalyst employed in the polymerization reaction varies with the choice of monomers to be polymerized and the choice of components of the catalyst system, but is generally in the range of from about 0.005 to 0.2 mole of catalyst per 100 moles of monomers. r

The conditions at which the polymerization reaction is conducted can vary over a wide range. Generally, temperatures ranging from to 50 C. can be used; however, temperatures ranging from -30 to 30 C. are preferred. The pressure at which the polymerization is carried out is not critical and pressures ranging from 0.2 to 1000 p.s.i.g. can be employed in the polymerization reaction. Pressures in the range of from about 1 atmosphere to 10 atmospheres are most generally used. The reaction time used in the formation of the preferred copolymers and terpolymers depends in general upon the temperatures used. Generally, reaction times can vary from minutes to Weeks; however, it is more usual to use reaction times ranging from about 0.25 to 100 hours.

The reaction vessel can be constructed of any material that is inert to the reactants and diluents used, and is capable of withstanding the operating pressures. Reaction nace blacks and thermal blacks and/ or mineral fillers such as the oxides, hydroxides, carbonates, etc. of silicon, aluminum, magnesium, titanium, or the silicates or aluminates of the various elements indicated may be compounded with the elastomeric products of the present invessels made of glass, stainless steel and glass-lined steel 5 vention. are satisfactory. Polymers containing more than about 30 mole percent In a typical polymerization procedure, a glass reaction cyclopentadiene residues tend to be thermoplastic matevessel is charged with benzene and a catalytic amount of rials. Such polymers may be molded and pressed or cast triphenylmethyl tetrafluoroborate. To this mixture of catainto films. Lower molecular weight products of this type lyst and solvent is then introduced a monomer mixture are especially useful as components for varnish and paint consisting of tetrahydrofuran, cyclopentadiene and triformulations although the more insoluble high molecular methylene oxide. In general, about 0.005 to 0.2 mole of weight products can be used. These polymer products catalyst is used per 100 moles of monomer. The glass air-dry to ahard, tack-free surface. The elastomeric prodreaction vessel containing the reaction mixture is then ucts of this invention may be utilized in the preparation sealed and placed in a constant temperature bath, mainof tires, inner tubes, hose and tubing, wire and cable tained at a temperature ranging from 30 to +30 C. coatings, and mechanical goods, as well as for a wide The reaction may be carried out at atmospheric, subvariety Of coated and molded articles. atmospheric or superatmospheric pressures. The reaction This invention and its advantages will he better undervessel and its contents are continuously tumbled in the Stood y reference to the toiiewihg examples! constant temperature bath during the period of reaction.

Polymer isolation and catalyst removal can be achieved EXAMPLE 1 utilizing Vafiety 0t teehhiques- In one Procedure, the A series of polymerization tests were conducted to P y Solution is ihtfodlieed ihto excess hon-Solvent r illustrate the effectiveness of the catalyst system of the such as methanol Water to P P the p y present invention for the copolymerization of tetrahydrot0 Precipitation the P l/ solution can he Washed furan and cyclopentadiene. In every instance, the test was i aqueous acid or base to effectively remove and d carried out in a sealed glass reaction vessel. The reaction activate catalyst residues. If desired, additives and staystem was made up of dimepfree cyclopentadiene tetra. hiiiZeI'S y he introduced into the Polymer Solution Prior 6 hydrofuran and a triphenylmethyl hexachloroantimonate t0 PIeeiPitatiOh- Ah especially attractive finishing Process catalyst in the amounts specified in each of the runs. The involves the introduction of the P y Solution o a polymerization was conducted in bulk at a temperature of bOdY Of hOt water containing acidic 01 basic deashing 7 C for a, period of '72 hours After the completion of agents and Whatever add tives or Stabilizers may be tie: the polymerization reaction the total reaction mixture was sired. poured into excess methanol to precipitate the polymer The copolymer and terpolymer products of the present product. The polymer product thus obtained was then invention as procured by the above process exhibit molecvacuum oven dried and tests were conducted to determine ular weights ranging from about 500 to 1,000,000. Molecthe polymer inherent viscosity and polymer structure. ular weight determinations in the case Of high molecular Inherent viscosity measurements were made in benzene weight polymers are determined by membrane osmom- 40 solution at C. Copolymer structure, i.e. the amount etry or in the case of lower molecular weight materials of cyclopentadiene and tetrahydrofuran present in the by vapor phase osmometry. The copolymer and terpolymer, was determined by nuclear magnetic resonance polymer products exhibit intrinsic viscosities ranging from measurements of 10% solutions in carbon tetrachloride. about 0.05 to 5.0 as determined in benzene at a tempera- The results of the tests are set forth in Table I below:

TABLE I Feed Polymer Run CPD 1 THF 3 Mole Catalyst Yield Inherent Mole Mole (1111.) (ml.) percent (1111;) (gr.) Viscosity percent percent CPD 1 (avg.) CPD 1 THF 1 19.5 2.5 3.6 1.95 3.4 94.6 19.0 5.2 40 5.4 1.88 8.0 92.0 18.0 11.0 40 5. 2 1. 37 14. 0 86.0 50. 0 16. 4 120 11. 9 0.85 46 54 l cyclopentadiene. 2 Tetrahydrofuran.

ture of 25 C. and a polymer concentration of from 0.05 The above tests indicate that copolymers of tetrahydroto 0.50 gram of polymer per 100 cc. of solution. The polyfuran and cyclopentadiene containing various amounts of mers produced are soluble in tetrahydrofuran, benzene, eac of the monomers are readily formed with the catachloroform, toluene, cyclohexane, and methylene chlo- Y System i the Present lIWeIltlOn- The PQ Y thus ride formed contain varied amounts of unsaturatlon.

The copolymers and terpolymers of this invention can The Polymer f f l Run 4 of a I was formu' be designed for different end uses. The high molecular late? as a solutlfm contammg 5 Solids m toluene for weight P y containing at least about 75 mole p testing as a varnish. It was applied to a carbon steel panel and a1r-dr1ed to a tack-free finish in two hours. After dry Cent tetrahydhoiman fesldiles with the rerflammg 25% ing for a total period of five hours at room temperature, of the Fomposmon i either cyclopentadlene or f the film exhibited an H hardness in a pencil-hardness test. pentadlene and an oxlrane or oxetane compound residues, are highly useful elastomers. The products may be vul- EXAMPLE cafuzed usmg Sulfur and accelaraiors Such as A further series of tests were conducted to demonstrate thlazyl d1su1fide metcapwbeflzethlaleie i the effectiveness of the catalyst system of the present henzothlalyi Suifehamlde, teihlriilih diethyi dithioearha' invention for the terpolymerization of tetrahydrofuran, mate, etc. Carbon blacks such as the channel blacks, furcyclopentadiene, and an epoxide compound. Each test was carried out in a 30 ml. glass reaction vessel using 40 mgm. of triphenylmethyl hexachloroantimonate. The'polymerization was conducted in bulk at a temperature of 7 C. for a period of 40 hours. The amounts of monomers used in the formation of thepolymer are set forthin the table. Inherent viscosity measurements and the percentage of epoxide compound present in the polymer using infrared spectroscopy" were determined. The results of the tests are set forth in Table II below:

part by Weight of phenyl-B-naphthylamine, 1 part by weibht of (PX-441) 2,6-ditertiary butyl-p-cresol, 2 parts by weight stearic acid, 5 parts by weight zinc oxide, 2 parts by weight white lead, 2 parts by weight sulfur, 1 part by weight (Altax) benzothiazyl disulfide, and 1.5 parts by weight (Tuads) tetramethyl thiuram disulfide. The total composition was then cured into a pad at 300 F. for a period of 60 minutes. The pad was subsequently cut into a standard dumbell and tested under ASTM conditions of temperature and humidity on a Scott Micro- TABLE II F d T l Tensile Tester. The cured sample exhlblted a tenslle Run erpO ymer strength of 1330 p.s.i. and an elongation at break of CPD 1 AGE 2 THF Yield Inherent Mole pe 350%. The modulus at 300% extension. was 1250 p.s.i. (mm (ml') (ml) (gl') Vlscoslty centAGm The cured polymers of the present invention also ex- 8 8 8-33 hibit solvent and oil resistant properties. For example, 3::::::: g; 7 the weight percent increase of the above cured terpolymer I I V r in ASTM No. 3 oil at 100 C. was 146%. Styrene-butay f i zAllylglyPldylelherf diene rubber or butyl rubber vulcanizates, with similar Dunng the course of te'rpolymerfzatlon a transient proportions of fillers, illustrate a weight percent increase blue color of the polymenzatlon solution was observed. 20 ranging f 300 to 400%, or even more, in the same test T 1? blue color alsopmfiuced dunng h copolymer- The room temperature weight percent increase in ASTM a offetlfahydrofuran Wlth cyclopentadlwe- Thls No. 3 oil of the cured terpolymers of this invention Was servation lndlcates that the small amounts of cyclopentaa vulcanizate f Neoprene W, a Welbknown, dlene pl'ffsent were itipolymenzed the expenments resistant elastomer, showed a 34% weight increase in the set forth in Table II with the catalyst system-of the pres- 25 Same test ent invention. The polymers obtained contained minor amounts of unsaturation and are readily vulcanized to sol- EXAMPLE 5 vent and oll'reslstam vulcamzates' Bis[4,4 diphenylmethyljbibenzyl bis(hexachloro- EXAMPLE 3 I antimonate) was prepared by reacting 0.5 gram of 4,4- .An additional series of tests was conducted to demonbls(chlorqdlphePylmethyl)blbenlyl of carbon strate the flexibility possible with the process of this -intetrachlonde i two the thoretlcafl amount vention by the preparation of terpolymers of tetrahydrof mlxmg a brown l lmmedlatelY PreclP furan cyclopent-adiene and a third Oxirane or oxetane itated. This product was recrystallized from a mixture of Each test carried b in a 30 glass carbon tetrachloride and methylene chloride and analyzed reaction vessel using amounts of triphenylmethylhexachloo for carbonahydrogen and chlonne i iroantimonate catalyst specified in each of the runs. Polym- The deslred Product has an emplrl-cal formula of erizations for all charges were carried out in bulk at a C4H32C112Sb2 wlth a calculated carbon content of 40-65 temperature of 70 for hours. The amounts of wt. percent, a hydrogen content of 2.73 wt. percent and monomers used in thepformatiion of the polymfirs are Set 40 a chlorine content of 36.01 wt. percent. The analysis reforth in the table. Polymer products were isolated from vealed a carbon content of 40'94 P f a hydro the reaction solution by precipitation into methanol. All gen content of Percent a a chlonne content of products were insoluble in this solvent except the product 3596 i Percentfrom Run 3 Where the amounts of propylene Oxide A mixture consisting of 2 ml. cyclopentadiene and 18 residues in the. terpolymer were sufficient to lead to solu- P Of tetrahyfimfuran PQlymerlzed Wllih a 40 mg. P bility in methanol. In this instance the polymer product non of the be carbomum Ion Salt p p above a a was isolated by evaporatingthereaction solvent a d the temperature of 7 C. for 72 hours. The resulting polymer methanol from the product. The results of the tests are is an elastomeric substance that is readily cured with sulset forth in Table III below: fur and conventional accelerators.

TABLE III Run THF 1 CPD 2 PO 8 BOMO 4 Catalyst Yield Inherent;

(mg) (gr.) Viscosity 6 1 20 1 1 0 40 15.4 1.20 2 2o 1 4 0 10.2 0. 94 3 20 2 10 o 50 5.8 0. 4 20 1 o 1 40 7.8 1.04

1 'Ietrahydroiuran (in ml.). 2 Cyclopentadiene (in ml.). 3 Propylene oxide (in ml). 4 3,3-bis(chloromethyl) oxetane (in ml.). 5 Determined in benzene at 25 C.

The data of Table III above demonstrate that terpolymers consisting of tetrahydrofu-ran, cyclopentadien and various other oxirane and oxetane compounds can be prepared according to the process of this invention. The terpolymers secured contain minor amounts of unsaturation and are readily vulcanized with conventional curing agents and accelerators.

EXAMPLE 4 To demonstrate the curability of certain types of the polymers formed with the catalyst system of the present invention, 100 parts by weight of the polymer of Run 1 of Table II were compounded on a rubber roll mill with 50 parts by weight of high abrasion furnace black, 1

Further advantages of this invention will be apparent to those skilled in the art. Polymers of tetrahydrofuran, cyclopentadiene and an epoxide compound can be prepared with the process of the present invention. It is to be understood that this invention is not limited to the specific examples set forth herein, which have been ofiered merely as illustrations, and that modifications may be made 70 without departing from the spirit and scope of the appended claims.

What is claimed is: 1. A polymer comprising tetrahydrofuran polymerized through ring opening at the oxygen atom with a monomer system selected from the group consisting of cyclopentadiene and a mixture of cyclopentadiene and an epoxide compound having the general formula:

wherein n is an integer of 0 to 1; and R -R are selected from the group consisting of hydrogen, C to C alkyls, C to C haloalkyls, C to C aryls, and C to C alkenyl ethers, at least one of said R and R is hydrogen when n is equal to .0; and wherein said epoxide also polymerizes through the ring opening at the oxygen atom said polymer having an intrinsic viscosity in the range of about 0.05 to 5.0 as determined in benzene at a temperature of about C. and a polymer concentration from about 0.05 to 0.50 g. of polymer/ 100 cc. of solution.

2. The composition of claim 1 wherein Rr-Re are C to C alkyls.

3. The composition of claim 1 wherein R to R are C to C haloalkyls.

4. The composition of claim 1 wherein said epoxide compound is selected from the group consisting of allyl glycidyl ether, 3,3-bis(chloromethyl) oxetane, and propylene oxide.

5. The composition of claim 1 wherein said polymer composition contains at least about 75 mole percent tetrahydrofuran residues.

6. The polymer composition of claim 5 sulfur-cured to an elastomeric vulcanizate.

7. The composition of claim 1 wherein said polymer composition contains at least about mole percent cyclopentadiene residues.

8. The composition of claim 5 wherein said monomer system is cyclopentadiene.

9. The composition of claim 5 wherein said monomer system is cyclopentadiene and allyl glycidyl ether.

10. The composition of claim 7 wherein said monomer system is cyclopentadiene.

11. A method for preparing tetrahydrofuran containing polymers which comprises contacting tetrahydrofuran with a monomer system selected from the group consisting of cyclopentadiene and a mixture of cyclopentadiene and an epoxide compound in the presence of an arylmethyl carbonium ion salt having the formula:

wherein Ar is selected from the class consisting of phenyl groups, naphthyl groups and their alkyl substituted derivatives; M is selected from the class consisting of antimony, tin, aluminum, boron, zinc, iron, titanium,

zirconium, vanadium, and galenium; X is selected from the class consisting of chlorine, bromine, and fluorine; X is an integer of from 2 to 3; x+y is equal to 3; 2 equals the highest valence of M, plus 1; 11" is an integer of from 0 to 1 and when a equals 0, R is hydrogen and when a is equal to 1, R is an ethylene group.

12. The process of claim 11 wherein said epoxide compound is of the general formula:

wherein n is an integer of 0 to 1; and R -R are selected from the group consisting of hydrogen, C to C alkyls, C to C haloalkyls, C to C aryls, and C to C alkenyl ethers, at least one of R and R is hydrogen when n is equal to 0.

13. The process of claim 11 wherein said epoxide compound is selected irom the group consisting of allyl glycidyl ether, 3,3-bis (chloromethyl) oxetane, and propylene oxide.

14. The process of claim 13 wherein said arylmethyl carbonium ion salt is triphenylmethylhexachloroantimonate.

15. The process of claim 13 wherein said arylmethyl carbonium ion salt is bis[4,4'-diphenylmethyl]bibenzylbis (hexachloroantimonate) 16. The process of claim 13 wherein about 0.005 to 0.2 mole of arylmethyl carbonium ion salt is used per moles of monomers.

17. The process of claim 14 wherein the monomer system is cyclopentadiene.

18. The process of claim 14 wherein the monomer system is cyclopentadiene and allyl glycidyl ether.

19. The process of claim 14 wherein the monomer system is cyclopentadiene and propylene oxide.

References Cited UNITED STATES PATENTS 2,839,514 6/1958 Shokal et a1. 260-88.1 2,915,494 12/ 1959 Snoddon 260-821 3,278,502 10/1966 Huyser 2608O 3,354,133 11/1967 Hsieh 260-883 3,362,941 1/1968 Subbaraj 260--88.3

JOSEPH L. SCHOFER, Primary Examiner.

I. C. HAIGHT, Assistant Examiner.

US. Cl. X.R. 

